A U.S. appeals court judge known for his outspoken views described arguments by Wisconsin and Indiana defending bans on gay marriage as "totally implausible" on Thursday, in a ruling in favor of same-sex couples.

Judge Richard Posner, appointed by Republican President Ronald Reagan in 1981, wrote the unanimous decision on behalf of a three-judge panel of the Chicago-based 7th U.S. Circuit Court of Appeals. The court ruled against the bans.

The unusually swift decision, issued just over a week after the court heard oral arguments in two different cases, does not take immediate effect and is unlikely do so until the U.S. Supreme Court weighs in during its coming term.

The arguments advanced by both states in defense of the bans were "totally implausible," wrote Posner, 75 and the panel's lone Republican appointee.

"Heterosexuals get drunk and pregnant, producing unwanted children; their reward is to be allowed to marry. Homosexual couples do not produce unwanted children; their reward is to be denied the right to marry. Go figure," Posner said.

Posner has written dozens of books, including one about economics and intellectual property law. He also is a founding author of a blog on law and economics.

Two years ago he engaged in an unusual public spat with Justice Antonin Scalia, a leading conservative on the Supreme Court. In a review of Scalia's new book, Posner wrote the justice's judicial opinions deviated from the strict, text-based approach to interpreting law espoused in his book. Scalia, also appointed by Reagan, publicly disagreed.

Equal protection

The ruling said the bans on gay marriage in the two states violated the U.S. Constitution's guarantee of equal protection under the law. Two other federal appeals courts have ruled the same way, striking down bans in Virginia, Utah and Oklahoma.

The Supreme Court is expected to weigh in on the gay marriage issue during its coming term, which starts in October and ends in June 2015.

More than 30 courts overall have ruled in favor of gay marriage since a Supreme Court ruling in June 2013 struck down a key part of the 1996 federal Defense of Marriage Act under which states could refuse to recognize same-sex marriages from other states. A federal judge in Louisiana bucked the trend on Wednesday when he upheld that state's ban.

Gay marriage is legal in 19 of the 50 states and in Washington, D.C.

Wisconsin will appeal the ruling, said a spokeswoman for the state's attorney general, J.B. Van Hollen, a Republican. “The attorney general has always believed that this case will ultimately be decided by the United States Supreme Court," spokeswoman Dana Brueck said.

Indiana Attorney General Greg Zoeller said in a statement that he will seek a suspension of the appeals court ruling and hopes for a quick decision from the Supreme Court.

Hoosiers Unite for Marriage, a gay rights group that backed the challenge to Indiana's ban, said in a statement that its members were "incredibly grateful" that the court ruled so quickly in favor of couples who want to get married.

Larry Dupuis, legal director of the American Civil Liberties Union of Wisconsin, who has helped litigate the case, said he hoped state officials would "see the light on this" and end their defense of the ban.